[mirror_ubuntu-jammy-kernel.git] / drivers / hwmon / shtc1.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* Sensirion SHTC1 humidity and temperature sensor driver
 *
 * Copyright (C) 2014 Sensirion AG, Switzerland
 * Author: Johannes Winkelmann <johannes.winkelmann@sensirion.com>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/platform_data/shtc1.h>

/* commands (high precision mode) */
static const unsigned char shtc1_cmd_measure_blocking_hpm[]    = { 0x7C, 0xA2 };
static const unsigned char shtc1_cmd_measure_nonblocking_hpm[] = { 0x78, 0x66 };

/* commands (low precision mode) */
static const unsigned char shtc1_cmd_measure_blocking_lpm[]    = { 0x64, 0x58 };
static const unsigned char shtc1_cmd_measure_nonblocking_lpm[] = { 0x60, 0x9c };

/* command for reading the ID register */
static const unsigned char shtc1_cmd_read_id_reg[]	       = { 0xef, 0xc8 };

/* constants for reading the ID register */
#define SHTC1_ID	  0x07
#define SHTC1_ID_REG_MASK 0x1f

/* delays for non-blocking i2c commands, both in us */
#define SHTC1_NONBLOCKING_WAIT_TIME_HPM  14400
#define SHTC1_NONBLOCKING_WAIT_TIME_LPM   1000

#define SHTC1_CMD_LENGTH      2
#define SHTC1_RESPONSE_LENGTH 6

struct shtc1_data {
	struct i2c_client *client;
	struct mutex update_lock;
	bool valid;
	unsigned long last_updated; /* in jiffies */

	const unsigned char *command;
	unsigned int nonblocking_wait_time; /* in us */

	struct shtc1_platform_data setup;

	int temperature; /* 1000 * temperature in dgr C */
	int humidity; /* 1000 * relative humidity in %RH */
};

static int shtc1_update_values(struct i2c_client *client,
			       struct shtc1_data *data,
			       char *buf, int bufsize)
{
	int ret = i2c_master_send(client, data->command, SHTC1_CMD_LENGTH);
	if (ret != SHTC1_CMD_LENGTH) {
		dev_err(&client->dev, "failed to send command: %d\n", ret);
		return ret < 0 ? ret : -EIO;
	}

	/*
	 * In blocking mode (clock stretching mode) the I2C bus
	 * is blocked for other traffic, thus the call to i2c_master_recv()
	 * will wait until the data is ready. For non blocking mode, we
	 * have to wait ourselves.
	 */
	if (!data->setup.blocking_io)
		usleep_range(data->nonblocking_wait_time,
			     data->nonblocking_wait_time + 1000);

	ret = i2c_master_recv(client, buf, bufsize);
	if (ret != bufsize) {
		dev_err(&client->dev, "failed to read values: %d\n", ret);
		return ret < 0 ? ret : -EIO;
	}

	return 0;
}

/* sysfs attributes */
static struct shtc1_data *shtc1_update_client(struct device *dev)
{
	struct shtc1_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	unsigned char buf[SHTC1_RESPONSE_LENGTH];
	int val;
	int ret = 0;

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ / 10) || !data->valid) {
		ret = shtc1_update_values(client, data, buf, sizeof(buf));
		if (ret)
			goto out;

		/*
		 * From datasheet:
		 * T = -45 + 175 * ST / 2^16
		 * RH = 100 * SRH / 2^16
		 *
		 * Adapted for integer fixed point (3 digit) arithmetic.
		 */
		val = be16_to_cpup((__be16 *)buf);
		data->temperature = ((21875 * val) >> 13) - 45000;
		val = be16_to_cpup((__be16 *)(buf + 3));
		data->humidity = ((12500 * val) >> 13);

		data->last_updated = jiffies;
		data->valid = true;
	}

out:
	mutex_unlock(&data->update_lock);

	return ret == 0 ? data : ERR_PTR(ret);
}

static ssize_t temp1_input_show(struct device *dev,
				struct device_attribute *attr,
				char *buf)
{
	struct shtc1_data *data = shtc1_update_client(dev);
	if (IS_ERR(data))
		return PTR_ERR(data);

	return sprintf(buf, "%d\n", data->temperature);
}

static ssize_t humidity1_input_show(struct device *dev,
				    struct device_attribute *attr, char *buf)
{
	struct shtc1_data *data = shtc1_update_client(dev);
	if (IS_ERR(data))
		return PTR_ERR(data);

	return sprintf(buf, "%d\n", data->humidity);
}

static DEVICE_ATTR_RO(temp1_input);
static DEVICE_ATTR_RO(humidity1_input);

static struct attribute *shtc1_attrs[] = {
	&dev_attr_temp1_input.attr,
	&dev_attr_humidity1_input.attr,
	NULL
};

ATTRIBUTE_GROUPS(shtc1);

static void shtc1_select_command(struct shtc1_data *data)
{
	if (data->setup.high_precision) {
		data->command = data->setup.blocking_io ?
				shtc1_cmd_measure_blocking_hpm :
				shtc1_cmd_measure_nonblocking_hpm;
		data->nonblocking_wait_time = SHTC1_NONBLOCKING_WAIT_TIME_HPM;

	} else {
		data->command = data->setup.blocking_io ?
				shtc1_cmd_measure_blocking_lpm :
				shtc1_cmd_measure_nonblocking_lpm;
		data->nonblocking_wait_time = SHTC1_NONBLOCKING_WAIT_TIME_LPM;
	}
}

static int shtc1_probe(struct i2c_client *client,
		       const struct i2c_device_id *id)
{
	int ret;
	char id_reg[2];
	struct shtc1_data *data;
	struct device *hwmon_dev;
	struct i2c_adapter *adap = client->adapter;
	struct device *dev = &client->dev;

	if (!i2c_check_functionality(adap, I2C_FUNC_I2C)) {
		dev_err(dev, "plain i2c transactions not supported\n");
		return -ENODEV;
	}

	ret = i2c_master_send(client, shtc1_cmd_read_id_reg, SHTC1_CMD_LENGTH);
	if (ret != SHTC1_CMD_LENGTH) {
		dev_err(dev, "could not send read_id_reg command: %d\n", ret);
		return ret < 0 ? ret : -ENODEV;
	}
	ret = i2c_master_recv(client, id_reg, sizeof(id_reg));
	if (ret != sizeof(id_reg)) {
		dev_err(dev, "could not read ID register: %d\n", ret);
		return -ENODEV;
	}
	if ((id_reg[1] & SHTC1_ID_REG_MASK) != SHTC1_ID) {
		dev_err(dev, "ID register doesn't match\n");
		return -ENODEV;
	}

	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->setup.blocking_io = false;
	data->setup.high_precision = true;
	data->client = client;

	if (client->dev.platform_data)
		data->setup = *(struct shtc1_platform_data *)dev->platform_data;
	shtc1_select_command(data);
	mutex_init(&data->update_lock);

	hwmon_dev = devm_hwmon_device_register_with_groups(dev,
							   client->name,
							   data,
							   shtc1_groups);
	if (IS_ERR(hwmon_dev))
		dev_dbg(dev, "unable to register hwmon device\n");

	return PTR_ERR_OR_ZERO(hwmon_dev);
}

/* device ID table */
static const struct i2c_device_id shtc1_id[] = {
	{ "shtc1", 0 },
	{ "shtw1", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, shtc1_id);

static struct i2c_driver shtc1_i2c_driver = {
	.driver.name  = "shtc1",
	.probe        = shtc1_probe,
	.id_table     = shtc1_id,
};

module_i2c_driver(shtc1_i2c_driver);

MODULE_AUTHOR("Johannes Winkelmann <johannes.winkelmann@sensirion.com>");
MODULE_DESCRIPTION("Sensirion SHTC1 humidity and temperature sensor driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
c942fddf	1	// SPDX-License-Identifier: GPL-2.0-or-later
1a539d37 TP	2	/* Sensirion SHTC1 humidity and temperature sensor driver
	3	*
	4	* Copyright (C) 2014 Sensirion AG, Switzerland
	5	* Author: Johannes Winkelmann <johannes.winkelmann@sensirion.com>
1a539d37 TP	6	*/
	7
	8	#include <linux/module.h>
	9	#include <linux/init.h>
	10	#include <linux/slab.h>
	11	#include <linux/i2c.h>
	12	#include <linux/hwmon.h>
	13	#include <linux/hwmon-sysfs.h>
	14	#include <linux/err.h>
	15	#include <linux/delay.h>
	16	#include <linux/platform_data/shtc1.h>
	17
	18	/* commands (high precision mode) */
	19	static const unsigned char shtc1_cmd_measure_blocking_hpm[] = { 0x7C, 0xA2 };
	20	static const unsigned char shtc1_cmd_measure_nonblocking_hpm[] = { 0x78, 0x66 };
	21
	22	/* commands (low precision mode) */
	23	static const unsigned char shtc1_cmd_measure_blocking_lpm[] = { 0x64, 0x58 };
	24	static const unsigned char shtc1_cmd_measure_nonblocking_lpm[] = { 0x60, 0x9c };
	25
	26	/* command for reading the ID register */
	27	static const unsigned char shtc1_cmd_read_id_reg[] = { 0xef, 0xc8 };
	28
	29	/* constants for reading the ID register */
	30	#define SHTC1_ID 0x07
	31	#define SHTC1_ID_REG_MASK 0x1f
	32
	33	/* delays for non-blocking i2c commands, both in us */
	34	#define SHTC1_NONBLOCKING_WAIT_TIME_HPM 14400
	35	#define SHTC1_NONBLOCKING_WAIT_TIME_LPM 1000
	36
	37	#define SHTC1_CMD_LENGTH 2
	38	#define SHTC1_RESPONSE_LENGTH 6
	39
	40	struct shtc1_data {
	41	struct i2c_client *client;
	42	struct mutex update_lock;
	43	bool valid;
	44	unsigned long last_updated; /* in jiffies */
	45
	46	const unsigned char *command;
	47	unsigned int nonblocking_wait_time; /* in us */
	48
	49	struct shtc1_platform_data setup;
	50
	51	int temperature; /* 1000 * temperature in dgr C */
	52	int humidity; /* 1000 * relative humidity in %RH */
	53	};
	54
	55	static int shtc1_update_values(struct i2c_client *client,
	56	struct shtc1_data *data,
	57	char *buf, int bufsize)
	58	{
	59	int ret = i2c_master_send(client, data->command, SHTC1_CMD_LENGTH);
	60	if (ret != SHTC1_CMD_LENGTH) {
	61	dev_err(&client->dev, "failed to send command: %d\n", ret);
	62	return ret < 0 ? ret : -EIO;
	63	}
	64
	65	/*
	66	* In blocking mode (clock stretching mode) the I2C bus
	67	* is blocked for other traffic, thus the call to i2c_master_recv()
	68	* will wait until the data is ready. For non blocking mode, we
	69	* have to wait ourselves.
70	*/
71	if (!data->setup.blocking_io)
72	usleep_range(data->nonblocking_wait_time,
73	data->nonblocking_wait_time + 1000);
74
75	ret = i2c_master_recv(client, buf, bufsize);
76	if (ret != bufsize) {
77	dev_err(&client->dev, "failed to read values: %d\n", ret);
78	return ret < 0 ? ret : -EIO;
79	}
80
81	return 0;
82	}
83
84	/* sysfs attributes */
85	static struct shtc1_data shtc1_update_client(struct device dev)
86	{
87	struct shtc1_data *data = dev_get_drvdata(dev);
88	struct i2c_client *client = data->client;
89	unsigned char buf[SHTC1_RESPONSE_LENGTH];
90	int val;
91	int ret = 0;
92
93	mutex_lock(&data->update_lock);
94
95	if (time_after(jiffies, data->last_updated + HZ / 10) \|\| !data->valid) {
96	ret = shtc1_update_values(client, data, buf, sizeof(buf));
97	if (ret)
98	goto out;
99
100	/*
101	* From datasheet:
102	* T = -45 + 175 * ST / 2^16
103	* RH = 100 * SRH / 2^16
104	*
105	* Adapted for integer fixed point (3 digit) arithmetic.
106	*/
107	val = be16_to_cpup((__be16 *)buf);
108	data->temperature = ((21875 * val) >> 13) - 45000;
109	val = be16_to_cpup((__be16 *)(buf + 3));
110	data->humidity = ((12500 * val) >> 13);
111
112	data->last_updated = jiffies;
113	data->valid = true;
114	}
115
116	out:
117	mutex_unlock(&data->update_lock);
118
119	return ret == 0 ? data : ERR_PTR(ret);
120	}
121
122	static ssize_t temp1_input_show(struct device *dev,
123	struct device_attribute *attr,
124	char *buf)
125	{
126	struct shtc1_data *data = shtc1_update_client(dev);
127	if (IS_ERR(data))
128	return PTR_ERR(data);
129
130	return sprintf(buf, "%d\n", data->temperature);
131	}
132
133	static ssize_t humidity1_input_show(struct device *dev,
134	struct device_attribute attr, char buf)
135	{
136	struct shtc1_data *data = shtc1_update_client(dev);
137	if (IS_ERR(data))
138	return PTR_ERR(data);
139
140	return sprintf(buf, "%d\n", data->humidity);
141	}
142
143	static DEVICE_ATTR_RO(temp1_input);
144	static DEVICE_ATTR_RO(humidity1_input);
145
146	static struct attribute *shtc1_attrs[] = {
147	&dev_attr_temp1_input.attr,
148	&dev_attr_humidity1_input.attr,
149	NULL
150	};
151
152	ATTRIBUTE_GROUPS(shtc1);
153
154	static void shtc1_select_command(struct shtc1_data *data)
155	{
156	if (data->setup.high_precision) {
157	data->command = data->setup.blocking_io ?
158	shtc1_cmd_measure_blocking_hpm :
159	shtc1_cmd_measure_nonblocking_hpm;
160	data->nonblocking_wait_time = SHTC1_NONBLOCKING_WAIT_TIME_HPM;
161
162	} else {
163	data->command = data->setup.blocking_io ?
164	shtc1_cmd_measure_blocking_lpm :
165	shtc1_cmd_measure_nonblocking_lpm;
166	data->nonblocking_wait_time = SHTC1_NONBLOCKING_WAIT_TIME_LPM;
167	}
168	}
169
170	static int shtc1_probe(struct i2c_client *client,
171	const struct i2c_device_id *id)
172	{
173	int ret;
174	char id_reg[2];
175	struct shtc1_data *data;
176	struct device *hwmon_dev;
177	struct i2c_adapter *adap = client->adapter;
178	struct device *dev = &client->dev;
179
180	if (!i2c_check_functionality(adap, I2C_FUNC_I2C)) {
181	dev_err(dev, "plain i2c transactions not supported\n");
182	return -ENODEV;
183	}
184
185	ret = i2c_master_send(client, shtc1_cmd_read_id_reg, SHTC1_CMD_LENGTH);
186	if (ret != SHTC1_CMD_LENGTH) {
187	dev_err(dev, "could not send read_id_reg command: %d\n", ret);
188	return ret < 0 ? ret : -ENODEV;
189	}
190	ret = i2c_master_recv(client, id_reg, sizeof(id_reg));
191	if (ret != sizeof(id_reg)) {
192	dev_err(dev, "could not read ID register: %d\n", ret);
193	return -ENODEV;
194	}
195	if ((id_reg[1] & SHTC1_ID_REG_MASK) != SHTC1_ID) {
196	dev_err(dev, "ID register doesn't match\n");
197	return -ENODEV;
198	}
199
200	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
201	if (!data)
202	return -ENOMEM;
203
204	data->setup.blocking_io = false;
205	data->setup.high_precision = true;
206	data->client = client;
207
208	if (client->dev.platform_data)
209	data->setup = (struct shtc1_platform_data )dev->platform_data;
210	shtc1_select_command(data);
211	mutex_init(&data->update_lock);
212
213	hwmon_dev = devm_hwmon_device_register_with_groups(dev,
214	client->name,
215	data,
216	shtc1_groups);
217	if (IS_ERR(hwmon_dev))
218	dev_dbg(dev, "unable to register hwmon device\n");
219
220	return PTR_ERR_OR_ZERO(hwmon_dev);
221	}
222
223	/* device ID table */
224	static const struct i2c_device_id shtc1_id[] = {
225	{ "shtc1", 0 },
226	{ "shtw1", 0 },
227	{ }
228	};
229	MODULE_DEVICE_TABLE(i2c, shtc1_id);
230
231	static struct i2c_driver shtc1_i2c_driver = {
232	.driver.name = "shtc1",
233	.probe = shtc1_probe,
234	.id_table = shtc1_id,
235	};
236
237	module_i2c_driver(shtc1_i2c_driver);
238
239	MODULE_AUTHOR("Johannes Winkelmann <johannes.winkelmann@sensirion.com>");
240	MODULE_DESCRIPTION("Sensirion SHTC1 humidity and temperature sensor driver");
241	MODULE_LICENSE("GPL");